Sanding attachment for portable electric drills



May 28, 1963 P. L. BAHR 3,091,061

SANDING ATTACHMENT FOR PORTABLE ELECTRIC DRILLS Filed Aug. 50, 1962 INVENTOR. PAUL L. BAH/P ATTORNEY United States Patent 01 bee 3,@9l,hl Patented May 28, M353 3,091,061 SANDING ATTACHMENT FOR PORTABLE ELECTRIC DRILLS Paul L. Bahr, 1460 W. Liberty St., Hubbard, Ohio Filed Aug. 30, 1962, Ser. No. 220,476 Claims. (Cl. 51-170) This. invention relates to a sanding device and more particularly to a device that may be used in sanding r finishing the curved surface of an object and which device incorporates a section of abrasive material such as sandpaper and means for imparting reciprocal motion to said section of abrasive material.

The principal object of the invention is the provision of a sanding attachment for a portable electric drill.

A further object of the invention is the provision of a sanding device which may be attached to a portable electric drill and operated thereby and which device incorporates means for converting the rotary motion of the portable electric drill to a suitable reciprocating motion.

A still further object of the invention is the provision of a sanding attachment for a portable electric drill which includes means directly engageable in the chuck portion of said electric drill.

A still further object of the invention is the provision of a sanding device incorporating an elongated flexible member and means for imparting reciprocating motion thereto and including means for detachably securing a strip of abrasive material such as sandpaper to said elongated flexible member.

The sanding attachment disclosed herein comprises a simple and efficient device for sanding various objects including particularly those of circular cross section, as, for example, in the removing of paint, enamel, varnish and other finishes from furniture having cross sectiona-lly circular legs, arms or other structural parts. The device of the present invention is arranged to be operated by a portable electric drill and more particularly by the chuck portion thereof in which the drill bit is normally positioned. In operation, the sanding attachment imparts a suitable back and forth movement to a section of flexible material which in turn carries a strip of sandpaper or the like so that when the strip of flexible material carrying the sandpaper is positioned around a cross sectionally circular object a suitable sanding action results.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being the intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention is illustrated in the accompanying drawing, wherein:

FIGURE 1 is a top plan view of the sanding attachment showing the same engaged upon a vertically positioned cross sectionally circular object to be sanded.

FIGURE 2 is a horizontal section on line 2-2 of FIG- URE 1.

FIGURE 3 is an enlarged cross section on line 33 of FIGURE 1.

By referring to the drawings and FIGURES 1 and 2 in particular, it will be seen that a cross sectionally cir cular object to be sanded has been indicated and generally indicated by the letter A. As disclosed herein, the object A is positioned vertically and the sanding attachment as seen in FIGURE 1 is disposed on a horizontal plane with a flexible member extending around approximately 'half the circumference of the object A. The flexible member 10 is preferably formed of fabric webbing or the like with its end portions 11 and 12 apertured and provided if desired with metal end pieces so that the ends 11 and 12 of the flexible member 18 may move relative to oppositely disposed extensions 13 and 14 of a T-shaped hollow body member 15 and with respect to fasteners 16 and 17 respectively which extend through the apertures in the ends 11 and 12 of the flexible member 10.

As illustrated in the disclosed embodiment of the invention the fastener i6 comprises a bolt threadably engaged in a threaded opening in the extension 13 of the T-shaped hollow body member 15 and the fastener 17 comprises a bifurcated snap-in type fastener registerable in a suitably shaped annularly grooved opening in the extension 14. It Will thus be seen that the fastener 17 may be conveniently engaged and disengaged which permits the flexible member 1% to be positioned about the object A and removed therefrom.

The flexible member 10 is preferably provided with a rubber-like inner surface 18 so that an elongated section of abrasive material such as sandpaper 19 may be placed 'thereagainst and held in assembly therewith, as illustrated, by a pair of similarly formed clips or buckles 20 and 21 and it will be understood by those skilled in the art that the clips or buckles 2d and 21 may be readily disengaged and that they serve to hold the section of sandpaper 19 in the assembly as illustrated and are re moved and replaced whenever the sandpaper 19 is re moved and replaced.

The T-shaped body member 15 which is hollow has an annular bearing 22 secured thereto and a thrust and retainer collar 23 is positioned immediately adjacent thereto and provided with a threaded aperture in which a set screw 24 is positioned. The extensions 13 and 14 heretofore referred to may be integrally formed with the body member 15 or may be secured thereto so as to be fixed relative thereto. A secondary collar 25 is positioned adjacent the body member 15 and is provided with a threaded aperture in which a secondary set screw 26 is engaged. A shaft 27 having a portion thereof positioned at an angle of approximately 78 from the axial center line of the remaining portion thereof is engaged in the hollow body member 15, the bearing 22 and the collars 23 and 25 respectively and said collars 2,3 and 25 are secured to said shaft by the set screws 24 and 26 respectively and revolve therewith.

It will be observed that the bend in the shaft 27 which, as aforesaid, causes one portion thereof to lie at an angle of approximately 7 or 8 relative to the axial center line of the other portion thereof is located on the transverse center line of the hollow body member 15 as indicated by a center line in FIGURE 1 of the drawings. By referring to FIGURE 2 of the drawings, it will be seen that the angular portion of the shaft 27 (relative to the body member E5, the bearing 22 and the thrust and retainer collar 23) extends outwardly a suitable distance for engagement in the chuck of a portable electric drill (not shown).

It will be understood by those skilled in the art that when the shaft 27 is so engaged and the portable electric drill and its chuck held in a relatively fixed position, the end portion of the shaft 27 lying within the hollow body member 15, hearing 22 and the thrust and retainer collar 23 will move in a circular motion relative to the longitudinal axis of the portion of the shaft 27 engaged in the chuck of the portable electric drill. This motion will impart opposite circular mot-ions to the oppositely disposed extensions 13 and 14 of the hollow body member 15 and cause the same to move the fasteners 16 and 17 and .hence the ends of the flexible member 10 in circular patterns relative to the transverse axis of the body mem ber 15 with the net result that the ends 11' and 12 of the flexible member 16 move back and forth in oppositely disposed relation and therefore impart a desirable back and forth sanding action relative to the engaged surface of the article A. Solid lines adjacent the center line on' FIGURE 1 illustrate the degree of motion achieved.

The degree of reciprocal motion imparted the ends of the flexible member may be varied by the formation and size of the body member and its extensions 13 and 14 to which the ends 11 and 12 of the flexible member 10 are secured and the same is true with respect to the de gree of the angle between the two portions of the shaft 27.

In FIGURE 2 of the drawings, a side elevation of the clip may be seen that it will be understood that it includes a similar depending portion engaging the outer surface of the flexible member 10 as seen in the top plan view of FIGURE 1.

The location of the bend in the shaft 27 is illustrated in the cross section comprising FIGURE 2 as being located exactly upon the transverse axis or center line of the hollow body member 15. By referring now to FIG- URE 3 of the drawings, an enlarged cross sectional elevation of :a portion of the sanding assembly may be seen to comprise the flexible member 10, the rubber coating 18 and the sandpaper or other abrasive material 19, and it will be seen that they are positioned in close proximity to one another.

It will be obvious to those skilled in the art that if desired a bracket or mounting device may be attached to the T-shaped hollow body member 15 and/or its extensions '13 and 14 and engaged upon the portable electric drill to contribute to the relatively stationary positioning of the T-shaped body member relative to the rotating shaft 27 while at the same time permitting it to move in its hereinbefore described manner to elfect the reciprocal motion necessary on the part of the flexible member 10.

It willthus be seen that a sanding attachment for a portable electric drill has been disclosed and having thus described my invention, what I claim is:

1. A sanding attachment comprising a T-shaped hollow body member, a bent shaft partially disposed in said T-sh-aped hollow body member and arranged to rotate therein, means secured to said bent shaft arranged to retain said bent shaft in said T-shaped body member, oppositely disposed transverse extensions on said T-shaped body member, an elongated flexible member having apertured ends and fasteners loosely securing said apertured ends of said elongated flexible member to the outer ends of said transverse extensions, a strip of flexible abrasive material and means for detachably securing said strip of flexible abrasive material to said flexible member between the ends thereof.

2. The sanding attachment set forth in claim 1 and wherein the means for-securing the strip of flexiblea'bra- 'sive material to said flexible member comprise metal clips.

3. The sanding attachment set forth in claim 1 and wherein an annular bearing is secured to said T-shaped hollow body member and so arranged to engage said bent shaft adjacent one end thereof. t

4. The sanding attachment set forth in claim 1 and wherein the means secured to said bent shaft comprise collars which are secured to said bent shaft on the opposite ends of said T-tshaped hollow body member.

5. The sanding attachment set forth, in claim 1 and wherein the bend in said bent shaft lies on the transverse axis of the T-shaped hollow body member.

References Cited in-the file of this patent UNITED STATES PATENTS 987,511 Toth Mar. 21, 1911 1,081,285 Flinker Dec. 9, 1913' 2,170,792 Brooke Aug. 29, 1939 2,258,733 Bracket Oct. 14, 1941 FOREIGN PATENTS 1,248,980 France Nov. 14, 1960 

1. A SANDING ATTACHMENT COMPRISING A T-SHAPED HOLLOW BODY MEMBER, A BENT SHAFT PARTIALLY DISPOSED IN SAID T-SHAPED HOLLOW BODY MEMBER AND ARRANGED TO ROTATE THEREIN, MEANS SECURED TO SAID BENT SHAFT ARRANGED TO RETAIN SAID BENT SHAFT IN SAID T-SHAPED BODY MEMBER, OPPOSITELY DISPOSED TRANSVERSE EXTENSIONS ON SAID T-SHAPED BODY MEMBER, AN ELONGATED FLEXIBLE MEMBER TO THE OUTER APERTURED ENDS AND FASTENERS LOOSELY SECURING SAID APERTURED ENDS OF SAID ELONGATED FLEXIBLE MEMBER TO THE OTHER ENDS OF SAID TRANSVERSE EXTENSIONS, A STRIP OF FLEXIBLE ABRASIVE MATERIAL AND MEANS FOR DETACHABLY SECURING SAID STRIP OF FLEXIBLE ABRASIVE MATERIAL TO SAID FLEXIBLE MEMBER BETWEEN THE ENDS THEREOF. 